Biology 1001A Study Guide - Midterm Guide: Complementary Dna, Gene Duplication, Membrane Protein

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coffeerhinoceros93

31 Oct 2018

School

Western University

Department

Biology

Course

Biology 1001A

Professor

Beth Mac Dougall Shackleton Tom Haffie

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Document Summary

Cha(cid:396)a(cid:272)te(cid:396)isti(cid:272)s of (cid:448)i(cid:396)uses a(cid:374)d (cid:449)h(cid:455) the(cid:455) a(cid:396)e (cid:374)ot ge(cid:374)e(cid:396)all(cid:455) (cid:272)o(cid:374)side(cid:396)ed to (cid:271)e (cid:862)ali(cid:448)e(cid:863). Viruses are one ore more nucleic acid molecules surrounded by a protein coat (capsid). Some capsids may be e(cid:374)(cid:272)losed i(cid:374) a(cid:374) e(cid:374)(cid:448)elope f(cid:396)o(cid:373) the host (cid:272)ell"s (cid:373)e(cid:373)(cid:271)(cid:396)a(cid:374)e. the(cid:396)e a(cid:396)e t(cid:449)o (cid:271)asi(cid:272) structures of viruses: helical (protein subunits in rodlike structure around genome) and polyhedral (coat proteins make triangle units). They lack several basic properties of life, such as lack of mobility and not being able to reproduce, as well as not having a metabolizing system. This classifies them as infectious biological particles rather than organisms: why viral infections are usually difficult to treat with drugs, and exceptions to this general principle. Viral infections are usually difficult to treat with drugs because they are hidden in the host cell and so it is difficult to locate and attack virus-specific products. An exception to this general principle is when a virus uses its own polymerase.

Related Questions

1. A mutation in the gene encoding the integrase enzyme rendersthe protein non-functional. How would the affect the HIV infectioncycle?

Formation of the provirus would bestopped.

Reverse transcription would nolonger be possible.

The gp120 glycoprotein would nolonger be able to bind to the CCR5 receptor.

Cutting and assembling the capsid would be halted.

2. If the viral gene is AUGCCCAGG and the mRNA used to make theviral protein is UACGGGUCC, then the virus is a :

Negative strand RNA virus

Double stranded DNA virus

Retrovirus

Positive strand RNA virus

3. Would treating prions with enzymes that digest nucleotides bean effective neutralization method?

No, prions lack amino acids.

Yes, prion nucleic acids would besusceptible to enzymatic digestion.

No, prions lack phosphodiesterbonds and would not be subject to digestion by these types ofenzymes.

Yes, the bonds between the amino acids would be hydrolyzed.

4. Most Americans born before 1970 have a permanent scar ontheir shoulders from the smallpox vaccine. Why don't youngerAmericans have one?

Smallpox has been eradicated by aworldwide vaccination program.

Smallpox is no longer lethal.

A safer less damaging vaccine wasdeveloped in the early 1970's.

The vaccine is no longer effective due to antigenic shift.

5. What kind of pathogen would retain its ability to causeinfections after being treated with powerful proteolytic chemicalsthat would destroy all proteinaceous material?

A viroid

6. Select all of the false statements concerning AIDS.

AIDS kills the patient.

Patients die as a result ofopportunistic infections.

AIDS shuts down the immunesystem.

HIV therapy (HAART) can clear thevirus from the bloodstream.

HIV therapy (HAART) can clear the virus from the patient'sbody.

7. Why do viruses only infect specific types of cells?

Viruses only attack epithelialcells, such as the cells lining the lungs.

If a host cell is weakened, viruseshave an easier time infecting it.

The initial choice is random butonce a cell type is chosen it becomes the preferred host.

The host cells have the correctsurface receptor that the virus can fit into.

Viruses infect the first cells they encounter.

8. Nucleotide analogs are a class of drugs that are highlyeffective against many types of viruses. They work by halting thereplication of viral genes. They are equally effective at stoppingthe spread of prion diseases.

True

False

9. An experimental chemical has been shown to selectively cleavephosphodiester bonds. How would the affect a virus?

Dissociate the envelope

Fragment the genome

Hydrolyze the protein coating

Alter the host binding site

Digest the capsid

10. HIV uses cell surface receptors to enter host cells. Whydoes switching from a CCR5 co-receptor to a CXCR4 co-receptoreventually shut down the immune system?

	Macrophages have CCR5co-receptors.
	T-helper cells have CXCR4co-receptors.
	T-helper cells are not involved incoordinating immune responses.
	Only macrophages are killed byHIV.

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Biology 1001A Study Guide - Midterm Guide: Complementary Dna, Gene Duplication, Membrane Protein

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